Safety precautions in the woodworking shop require shields which surround whirling saw blades and project forwardly from the cutting edge thereof, the shield being arranged for pivotal movement on a horizontal axis so that as the piece to be cut is introduced to the shield, the shield is tilted upwardly to provide clearance for the piece introduction. As the piece passes beneath the shield and through the saw blade, the shield is brought back downwardly in a horizontal position over the piece being cut for protecting the operator from the saw.
There is no suggestion of any arrangement for stopping operation of the saw motor when the guard is tilted for introduction of the piece to be cut.
Inasmuch as there is nothing in the prior art on controlling the operation of the saw motor establishing the operating parameters that the guard must always be in operating position as actuated by the thickness of material being cut for the saw motor to run, and/or in the event that the operator should move away from the table without pushing the motor-stop button whereby a time-delay switch will automatically shut off the motor after the passage of the set period of time, there is thus an established need for a combination of electrical controls with an actuating mechanism for the guard which will perform these operations.